I recently replaced all the glow plugs on my 92 4x4 after replacing them my glow plug controller would no longer cycle. the glow plugs would heat for about 8to10 seconds and the go off it would not cycle thrue start up.( click on and off) I replaced the glowplug controller but it still does the same thing if I disconect two of the glow pugs it does not mater which two it then cycles normally. any ideas what would cause this?

 

What brand/type of GPs are you using.........

 

ford motorcraft

 

I can send you a test for the controller........ click on my name and email me.

Ask for: GP controller test..

Good info.....

If you have 2 or more bad GPs, the controller may not cycle at all.

Two problems that occur with the solid state ( 1987 to 1994 IDI engines ) GP systems. If a GP burns out ( circuit resistance goes up ), the controller cycles the GPs at a faster rate which doesn't let them get to max operating temp. If 2 or more GPs fail, the controller may not cycle the GPs at all ( very rapid or no clicking heard ). When you check the GPs, use an ohmmeter. A high resistance ( not necessarily burned out ) GP can cause circuit resistance to go up and the controller will then cycle the GPs too fast. You probably will not find this problem with a test light. Resistance spec for GPs = .5 to 1 ohm cold. Second problem. A poor controller ground ( black wire attached to valve cover stud ) will cause the controller to leave the GPs on longer, often damaging or failing them. If you are having mulitple GP failures, I would check closely the controller ground. Now the confusing part. Bad ground --> longer GP on time ( slower cycling ). Burned out GPs --> faster cycling If you have both situations, it may appear that the controller is cycling the GPs at the proper rate. Bad ground slows it up while the burned GPs speed it up ---> normal cycling. The system acts/sounds like it's working normally, but you have a hard starting concern.
By........DieselDon

Glow plug torque is 12 ft lbs, I always use antisieze on the threads.

 

Thanks PLC7.3
I tested the ground by running a wire from the battery ground to the stud where the controler ground is and that made no difference I did notice that many of the wires on the glow plug harness are starting to crack in several places Im not sure if this would cause this problem or not but I do think It is time to replace the harness.so before I go any further Im going to hunt down a new or used harness and then I will go though each glowplug.

 

What I did to be sure I had a excellent ground was to run a separate ground wire from the battery to the controler stud which had the black wire. Have not had a problem since.

 

I was able to find a new wire harness so I got that on order cost was 120.00. I should get it in about a week then I can start the prosess of elimination.

 

I added a huge braided stainless ground strap to the frame. No more glowplug relay problems............

 

You may want to check the resistance of each glow plug.
You may have one that is internally shorted when hot.

Temp dependant for the exact reading, but you should see between .75 and 1.5 ohms on each glow plug.

It does take a good digital multi meter to read the resistance though.
A cheap one may just show a dead short.

 

spec's on glow plugs is 5 ohms or less is good anything over 5 ohms is bad even 6 ohms

 

Sorry to leave you guys hanging on if I solved my problem or not. when I was taking off my banks air cleaner I noticed I had a crack on the intake manifold wear the bolt holds the air cleaner inplace. so I had to get a manifold then I had to order the valley pan/gasket. finally got all parts so now its time to get to work. In order for me to get the gasket / valley pan off I have to remove the injector pump. before I do this I would like some tips on removing it. I hear if you dont do it right you can mess things up.
So help please.
Thanks

 

leave the gear housing in place, mark the pump and housing so you can get the timing the same, you will need 5/16 12 point socket to remove three bolt that attach gear to pump, pull the pump and steel lines as one piece, offset wrench works good for three nuts that hold pump to housing

 

gabyski ......... click on my name and email me....... ask for IP R&R info

 

Thanks PLC7.3 for the IP info you sent me it was a big help. It was a lot less complicated then I thought it was going to be. I got the valley pan/ gasket in the Ip back on and the manifold back on. I still need to tighten everthing and then I can get back to my glow plug problem. I did the light test on each plug and the light came on for all. Im not quit clear on doing the resistance test. I tried but I got no reading. do I have to pull the plugs to check them or can I check them installed? I dont no much about using these meters. I have a cen-tech digital multimeter. It has 5 settings for oms 2000k, 200k, 20k, 2000, 200. which one do I want to set it to?
Thanks again to all for there input

 

The 200 setting should be fine.

One lead on the housing of the glow plug, the other on the connector.

You want to see between .5 and 1.5 ohms resistance.
A cheap meter will probably show 0 ohms which would be a dead short.
Most meters good enough to read the resistance that low will be auto ranging meters, but there are exceptions.

A higher resistance means the glow plugs will not be getting as hot as they should be as fast as they should.